Web Hosting Talk : Web Hosting Main Forums : Colocation and Data Centers : two HSRP routers, one server with dual NICs, no additional switches whatsoever

[OneLittleBird]

Dear all,

my provider gives me two HSRP routers (i.e. there is a single virtual hrsp IP and MAC address). I need to provide a single gateway to the provider, i.e. a single IP address (and ideally a single MAC).

I have a server with two NICs. I want to connect my server to these 2 HSRP routers without using any additional switches in between.


Is it possible? I would imagine so, as anything a switch does a server should be able to do too, with the right software. But how do I do this?

Is Intel NIC teaming - more specifically, SFT(switch fault tolerance) teaming - the right solution?

[OneLittleBird]

What about an even simpler solution - creating a network bridge in the OS with these two NICs? Both NICs will then have the same IP, right? And HSRP routers can send their traffic to either of the NICs?

Would this work?

[IDediServer Kevin]

OneLittleBird,

If the interface on the routers that is connecting to the server are setup for HSRP then the cheapest way would be to do that (bond the interfaces at the OS level).

[DUR0N]

I'm not sure if the Intel NIC's software supports HSRP. Usually they do active load balancing of some kind, or regular failover.

[MaB]

Originally Posted by DUR0N

I'm not sure if the Intel NIC's software supports HSRP. Usually they do active load balancing of some kind, or regular failover.

HSRP is run on the server providers routers, not the OPs server.

OneLittleBird, what you are looking for is NIC bonding.
- Instructions for CentOS / RedHat: http://www.cyberciti.biz/tips/linux-...interface.html and some more details http://www.howtoforge.com/network_card_bonding_centos

- http://www.cyberciti.biz/howto/quest...iver-howto.php - section 12.2 is basically what you'll be doing - it sounds like you'll be connected to two of their routers - to avoid any potentially confusing situations you may want to run in active-backup mode where only 1 NIC/mac address is active at a time.

If you're running windows, it might get a bit more complicated and specific to the OS and NIC drivers. You mention Intel teaming and Switch Fault Tolerance (SFT) - according to the Intel NIC teaming White Paper, SFT requires STP on your uplink - but you have no control over that. I think what you want is Adapter Fault Dolerance (AFT) which chooses a primary Active NIC and switches to a Standby NIC if the primary one fails.

I recommend that, when using bonding, you should be sure to do ARP/traffic monitoring to detect failures and not just link down monitoring. The Intel whitepaper says 'AFT uses four indicators to detect if a failover is needed: the primary’s link status, the primary’s hardware status, a probe mechanism between the members of the team, and the primary port’s packet receive counters.' so you should be set in that regard

Best of luck!

[IDediServer Kevin]

HSRP is cisco proprietary, something similar would be VRRP.

The closest thing in this situation to a switch is to use bonding, the issues comes with what bonding mode to use. Example is if you use failover based bonding it will only failover if the primary link goes hard down. Their are conditions where the router may not respond even with the link up (rare but it happens)

A switch is obviously a better solution

[OneLittleBird]

Dear all,

thanks very much for your responses!

Dear MaB, I am concerned that Intel AFT (adapter fault tolerance) would not be suitable, as it will most probably result in one NIC being used all the time. The router which it is connected to might be alive, but not acting as the HSRP router, as far as I understand; xcintrik also expresses this concern.

Dear xcintrik, I agree that a switch would be a much easier solution, and this is my backup solution, but I would strongly prefer to do it without any additional switches.



How about creating a network bridge with these two NICs in Windows? I am not sure what a "network bridge" is exactly. I only know vaguely what it is usually used for: namely, to merge two network segments. I do not need to bridge no segments. But I have a feeling that a Windows "network bridge" is in fact like a virtual switch (which is exactly what I need). There will be no nic redundancy in this case, which is fine with me. But would it work?

[IDediServer Kevin]

OneLittleBird,

What is a bridge technically?
They are a small switch, it learns where MAC addresses live and send traffic for that MAC to the port it responds from.

If you were to do this I would set your ARP timeout to be fairly low.